Find your files
On your old server, they're in the server's identity folder, server\<identity> (often server\my_server_identity). Stop that server, then download the save and map, proceduralmap.<size>.<seed>.<version>.sav and .map, and the player.*.db files, such as player.blueprints.<number>.db.
Upload it
- Match the map. In Settings, set World size and Seed to the numbers in the save's file name, proceduralmap.<size>.<seed>.<version>.sav, and press Save configuration.
- Stop the server. Press Stop in your dashboard.
- Upload the files. Open Files & SFTP, choose server/warp and press Upload to server/warp for the .sav, the .map and each player.*.db file. Files up to 96 MB upload in the browser; bigger ones go over SFTP, up to 2 GB.
- Wait for the safety scan. Press Refresh until every file shows Passed safety scan.
- Start the server. Press Start. The server loads the save for that size and seed.
Good to know
- A save only loads on the Rust version it was made with. After a forced wipe (Facepunch's monthly update, on the first Thursday of the month), an older save won't load.
- Oxide plugins: set Server software to Oxide (uMod) and upload plugins to oxide/plugins, their settings to oxide/config and their data to oxide/data.